import numpy as np
import pandas as pd
arr = np.random.randint(1,20,size=(3,3))
df = pd.DataFrame(arr,columns=['a','b','c'])
print('原始数据\n',df)
print('每列求和聚合\n',df.agg('sum'))
print('每列同时求和及平均值聚合\n',df.agg(['sum','mean']))

def rang(arr):
    return  arr.max() - arr.min()
print('每行分别求和，平均值和极差聚合\n',df.agg({0:'sum',1:'mean',2:rang},axis=1))